Flexible display devices are widely applicable to the fields that require curved display because of its bendable property. An existing flexible display device employs an organic light emitting diode as a light source. However, the organic light emitting diode is very sensitive to moisture and oxygen in the air, so there is a high requirement on package of the organic light emitting diode substrate of the flexible display device, and the package effect directly impacts on the life of the organic light emitting diode substrate.
In the package of an existing organic light emitting diode substrate, the manner of entire-surface adhesion with an adhesive is mostly used. The organic light emitting diode substrate which is packaged in the manner of entire-surface adhesion with an adhesive comprises a base substrate, a device layer formed thereon comprising an organic light emitting diode, and an adhesive whose entire surface is adhered to the device layer and the base substrate. Commonly used adhesives include a pressure sensitive adhesive and a thermos-curing adhesive. If a pressure sensitive adhesive is used as the adhesive, though the adhesion with the pressure sensitive adhesive is quite secure, the pressure sensitive adhesive itself has poor capability of blocking moisture and oxygen, thus it cannot provide enough protection for the organic light emitting diode. If a thermo-curing adhesive is used as the adhesive, though the thermos-curing adhesive has good capability of blocking moisture and oxygen, its adhesive strength is poor and particularly it is prone to peel off at edges, thus it cannot provide enough protection for the organic light emitting diode, either. Accordingly, in an existing organic light emitting diode substrate which is packaged in the manner of entire-surface adhesion with an adhesive, there exists a technical problem that the organic light emitting diode cannot be effectively isolated from moisture and oxygen in the air.